This is by far the most common question we receive. The short and easy answer is "Yes, absolutely." All of our upper receiver assemblies will fit on and be compatible with any standard-specification AR-15 lower receiver. No fitting or modifications are needed. If your lower receiver is made to standard AR-15 specifications, all of our upper receivers will work perfectly. We do not catalog all compatible lower receiver assemblies as this is not possible. We cannot confirm whether your lower receiver assembly is considered standard or mil-spec; you should contact the manufacturer to confirm this.

Yes, it will work. Each and every upper and lower receiver that we produce is designed around standard AR-15 specifications and can be used interchangeably with other mil-spec uppers and lowers as long as those products also require standard AR-15 specifications. We do not catalog all compatible upper receiver assemblies as this is not possible. We cannot confirm whether your upper receiver assembly is considered standard or mil-spec; you should contact the manufacturer to confirm this.

No, replacement of the buffer or buffer spring components is not required as long as the lower receiver is made to standard specifications. Buffer components should not be replaced if they are already standard. Please review the first Compatibility question. Both the .50 Beowulf® and our 6.5 Grendel weapons are properly designed to work specifically with standard-specification lower receiver assemblies containing standard-specification components. It is a common misconception that weapons with higher-than-average recoil, such as the .50 Beowulf®, automatically require a stronger buffer spring or heavier buffer to compensate for higher recoil in some way. This is not true of properly designed weapons. The AR-15 buffer and buffer spring are used only for the cycling of ammunition inside of the rifle. Recoil in an AR-15 rifle is almost entirely unrelated to the buffer components, especially with .50 Beowulf®. You can thank the 1,300 MPH projectile exiting the other end for the recoil.

A direct gas impingement weapon that allows too much gas pressure through the system will cause the buffer to bottom out very hard in the receiver extension, thus slightly increasing felt recoil. Our AR-15 products do not have this flaw in design.

Our products are specifically designed to use these particular, standard buffer components and no others just so that owners do not need to make specialized changes to their standard lower receivers.

Replacement of these standard buffer components when using our products will not reduce recoil or help the weapon manage the higher recoil in any way. The only possible result is the failure to cycle ammunition properly. To reduce felt recoil, we strongly encourage any customer to order a muzzle brake or compensator.

Will the .50 Beowulf® magazine feed .223 ammunition?

No, it will not.

Is the .50 Beowulf® legal in California?

Yes, it is. This question typically arises out of confusion of California state law surrounding the prohibition of the sale of .50 BMG rifles. The law applies exclusively to .50 BMG caliber rifles. The law does not apply to any other popular .50 caliber weapon, including .50 Beowulf®. If you are unfamiliar with .50 BMG or why .50 Beowulf® is so very dissimilar to it, below is a visual comparison.

While the .50 Beowulf® is designed to be the largest cartridge possible for the AR-15 platform, designed for the smaller 5.56 NATO or .223 Remington shown on top, it is less than half the size of the .50 BMG.

Components

My .50 Beowulf® has no ejection port cover. Did you forget to put it on?

No, we didn't forget it. The .50 Beowulf® was designed to not have an ejection port cover. Clearly, the port is much larger than a typical AR-15, so no, you cannot retrofit one. Trust us, you don't need it. As an addendum, the hinge points are left on the receiver because the upper receiver would cost more to manufacture by removing them from the design. They are not left specifically so that port doors can be retrofitted to the upper and we do not encourage this retrofitting.

No, we absolutely do not sell and have never sold these components. As we are the trademark holder and owner of the .50 Beowulf® cartridge, we manufacture these specialized components only for the production of the weapons we build. There are no exceptions to this rule. We do this to ensure that all .50 Beowulf® weapons are hand-made by our team and will work flawlessly. Some companies are now producing and selling knock-off, inferior, and potentially dangerous products that are either designated ".50 Beowulf" or are implied to be compatible. We are aware that some individuals are now building and selling non-functional complete rifles into the market that are made from these knock-off components. Please be aware that these components and any weapons built from them are not actual .50 Beowulf® products, are not genuine Alexander Arms® products, and are not tested or supported by Alexander Arms® in any way.

Can I use a collapsible butt stock on any Alexander Arms® lowers?

Any good quality, collapsible stock may be used on both the .50 Beowulf® and the 6.5 Grendel. The buffer should be the carbine type, which is externally-identical to the rifle buffer, but shorter. This buffer and spring is included with the stock. Some people choose to fit heavier buffers to slightly reduce the felt recoil, these being either the H1 type, which has a mix of steel and tungsten weights, or the H2 type, which has all tungsten weights, but the function of the gun must be checked to ensure that it is cycling fully. The heavy buffers designed for 9mm guns should not be used.

Will Alexander Arms® build a custom weapon or component for me?

We do not build custom weapons or components. Please see our Online Store to see all available products, parts, and options. If an item you wish to purchase is not displayed, it is not produced or sold by Alexander Arms®.

Can I purchase one of your factory assemblies without a particular component, such as the handguard?

No, we do not sell incomplete factory assemblies. We understand that the goal of many customers is to modify factory assemblies after receipt. All assemblies produced by Alexander Arms® are sold as fully-complete, fully-functional products. No exceptions can be made for this. Equally, we do not directly support customers in the modification of our products. Many modifications will void your product's warranty.

How effective is the muzzle brake on the .50 Beowulf®?

They are extremely effective. Felt recoil is somewhat subjective, but we estimate at least 30% and possibly up to 50% recoil reduction. Obviously, the muzzle blast noise is dramatically increased, but it makes the recoil feel more like a 20-gauge shotgun load instead of a 12-gauge shotgun load. It is the single best option you can buy with the weapon.

What are the diameters of .50 Beowulf® and 6.5 Grendel barrels?

.50 Beowulf® barrels are 0.980" diameter under the handguard and have a gas block diameter of 0.906". They are set to balance well between the hands and have a responsive feel. The 24" Advantage series 6.5 Grendel barrel is 0.890" under the handguard and 0.830" in front of the gas block. The profile provides a good foundation for shooting from a rest or bipod as the center of gravity of the gun is just behind the front hand position, but, equally, the barrel is not overly heavy and carries well. The weight of this barrel will not flex the standard receiver. The 19.5" and 20" 6.5 Grendel barrels are not only shorter, but are also a different contour to suit the differing application. This barrels are 0.770" under the handguard and moves the center of gravity backward to give a lighter handling and carrying rifle, but still capable from a bipod. The lightest 6.5 Grendel barrels are the now-discontinued Tactical series, the current Lite series, and the new Incursion model. These are 0.730" or less under the handguard and are very light for fast, responsive fire. Obviously, they are easy to carry, but, with the center of gravity near the rear hand, they are more of a challenge to shoot from a bipod or bags.

Will 6.5 Grendel or .50 Beowulf® cartridges feed from a .223 magazine?

6.5 Grendel and .50 Beowulf® cartridges will not feed properly or reliably from .223 magazines. Magazines for these cartridges are proprietary and can be purchased in our Online Store.

Usage and Effectiveness

What are the differences in barrel lengths and what length is better for given circumstances?

This mainly refers to the 6.5 Grendel as the .50 Beowulf® is best in a 16" barrel. The two 6.5 Grendel barrel lengths that are best suited for hunting are the 24" and 20" barrels. Shorter barrels may be applied, but, beyond slightly lighter weight and handier silhouette, they have no advantage and give up velocity. However, they are superb choices for general shooting or a utility rifle. A 24" 6.5 Grendel is well-suited to most hunting applications and, if one can live with the longer barrel, it is the most versatile of the 6.5 Grendel barrels. Accuracy is superb and the rifle is capable out to 1,000 yards and longer with the right ammunition. The balance of the gun assists stability in most position-shooting and it is excellent for use from a bipod. This one barrel length can bridge across a range of shooting tasks including long-range varmint work. A 20" barrel 6.5 Grendel is both shorter and lighter than the 24" gun, which is a big consideration if the gun must be carried. While it gives up some stability from a bipod, it is just a versatile.

Between the .50 Beowulf® and 6.5 Grendel, which gun is better for hunting and why?

It is very difficult to compare the .50 Beowulf® and the 6.5 Grendel when discussing hunting as they are very dissimilar guns and were built for very dissimilar hunting needs. Equally, hunting equipment is somewhat a personal choice, so it is only possible to give general advice. The .50 Beowulf® is particularly well-suited to close cover hunting where shots are not likely to exceed 200 yards, but it is imperative to anchor the game quickly. The heavy bullets from the Beowulf® are quite capable of breaking both shoulders of a moose, but the trajectory of the round will limit the range over which it can be used. Conversely, the 6.5 Grendel has the ability to operate from 0 to 1,000 yards with flat trajectories and bullets well-suited to deer and varmints. For general, all-around use, the 6.5 Grendel is probably superior, but it lacks the pure short-range smashing power of the .50 Beowulf®.

At what distance do the .50 Beowulf® and 6.5 Grendel perform most accurately?

The accuracy of any gun is a function of the velocity, the barrel twist rate, and the bullet with consideration given to atmospheric conditions and other fine measurements. The .50 Beowulf® is not optimized for accuracy, but will typically report 1-inch to 1.5-inch groups or better at 100 yards. Good hand-loads will shrink these groups, but the .50 Beowulf® is simply not a bench rifle. The 6.5 Grendel is capable of superb accuracy and the barrels are set up to capitalize on this ability at ranges of 200 yards and greater with bullets in the 90-grain to 130-grain class.

Caliber-Specific

To what is the recoil of the .50 Beowulf® most similar?

.50 Beowulf® recoil can best be described as similar to a light 12-gauge shotgun load. With the addition of the muzzle brake, the recoil is reduced between 30% and 50%, depending upon the shooter's perception.

What is the origin of the 6.5 Grendel cartridge?

The origin of the 6.5 Grendel may be traced back to the Soviet 7.62x39. This was modified for European competition, being necked down to form the 220 Russian. From here, Dr. Lou Palmisano and Ferris Pindel took the case and blew out the shoulder to create the 22 PPC and the 6mm PPC, which currently dominate bench rest competitions. In designing the 6.5 Grendel, the starting position was the PPC design, but it quickly became apparent that the caliber of the PPC was not as flexible as was needed. Early research with a wildcat 6.5 PPC also showed that the case lacked powder capacity, which, in turn, created pressure problems. The final 6.5 Grendel design draws on the PPC, but it is very much its own cartridge. The internal capacity was expanded by shifting the shoulder forward and the wall thicknesses in the neck and shoulder were increased to provide a more robust case capable of being fed within a semi-automatic rifle. Finally, the external taper of the case was adjusted for reliable feed in the magazine.

What is the origin of the .50 Beowulf® cartridge?

The .50 Beowulf® is the original big bore caliber for the AR style rifle. Its parentage is from the 50AE, which IMI introduced for the Desert Eagle pistol, but, as is obvious from its external appearance, this is a somewhat removed relation. From the ground up, the .50 Beowulf® is simply the biggest cartridge that can be fed reliably through an AR style mechanism without massive internal changes. The case length is set to allow the use of near standard magazines without having to use filler blocks and the volume allows the cartridge to work at very modest pressures, which is essential for such a large cartridge to be safe in the AR chassis.

What is the twist rate of the 20" and 24" 6.5 Grendel barrels?

The twist rate for the 6.5 Grendel 20" and 24" barrels is 1 turn in 9 inches. The twist rate for the 6.5 caliber must be carefully matched to the application for the best results, and one should note that we do not refer to 100 yard accuracy. This is because the ideal twist for such a range would not work well at longer ranges with heavier bullets.